This bug has been around for some time, but it is worse now because sublime auto reloads syntaxes (which I love).
Basically, if you reference a grammar or a repository that doesn't exist using the <key>include</key> tag, sublime segfaults.
It would be incredibly awesome if it could print a warning instead. It was really hard to debug this problem, which turned out to be a small typo. I had to use vi to fix it
For reference, I am on ubuntu 10.04 x64.